This application relates generally to power cables, and particularly to power cables for low frequency AC and DC applications, such as may be used for a driveline cable to power implantable mechanical circulatory support systems.
Ventricular assist devices, known as VADs, are implantable blood pumps used for both short-term (i.e., hours, days, months) and long-term applications (i.e., years or a lifetime) where a patient's heart is incapable of providing adequate circulation, for example, due to heart failure. According to the American Heart Association, more than five million Americans are living with heart failure, with about 670,000 new cases diagnosed every year. People with heart failure often have shortness of breath and fatigue. Years of living with blocked arteries or high blood pressure can leave your heart too weak to pump enough blood to your body. As symptoms worsen, advanced heart failure develops.
A patient suffering from heart failure, also called congestive heart failure, may use a VAD while awaiting a heart transplant or as a long term destination therapy. In another example, a patient may use a VAD while recovering from heart surgery. Thus, a VAD can supplement a weak heart (i.e., partial support) or can effectively replace the natural heart's function. VADs can be implanted in the patient's body and powered by an electrical power source inside or outside the patient's body through a driveline cable. The driveline cable can also be configured for data communication and control functions.
Since loss of power of an implanted VAD or failure to recharge an associated power supply poses life threatening consequences, to ensure continuous operation of the VAD, the driveline cable must provide a dependable electrical connection. Because the driveline cable may be subjected to movement or flexure over the course of its lifetime after implantation of the system, it is desirable if such driveline cables can withstand many cycles of use while maintaining integrity of the electrical connection. To provide such features, driveline cables often utilize high cost materials, such as drawn filled tubing wire and metal-to-metal composites, and may have a form factor (e.g., sizable diameter or shape) that require larger tunnels through tissues when implanted and/or larger incisions when percutaneously placed. It would be desirable to provide driveline power cables having improved durability at reduced cost of manufacture and reduced dimensions (e.g., diameter or shape), while maintaining the electrical and mechanical integrity of the power cable.